She directed officials to either "substantially reduce" or
decline to renew expiring contracts for private prison operators.

"They simply do not provide the same level of correctional
services, programs, and resources; they do not save substantially
on costs; and ... they do not maintain the same level of safety
and security," Yates wrote in the memo.

The move comes in the wake of a
blistering report from the Justice Department last week,
which found that private prisons are more dangerous than federal
Bureau of Prisons facilities — both for inmates and guards.

Private prisons — also known as "contract prisons" — first became
popularized as a solution to overcrowded government-run prisons.
But last week's report found substantially more safety and
security incidents occurring per capita than their government-run
counterparts.

In 2013, approximately 30,000 federal inmates were housed in
contract prisons — roughly 15% of all federal inmates. As of
December 2015, that number was about 22,000, or 12 percent.
In that time, though, the federal prison population dropped from
220,000 to 197,000.

The Office of the Inspector General noted in the report a series
of incidents at private prisons that have raised alarm, including
the death of a correctional officer at the Adams County
Correctional Center in Natchez, Mississippi, in 2012, as well as
riots and assault of prison staff at multiple facilities.

Private prisons have come under heightened scrutiny in recent
months, particularly after a
Mother Jones investigation revealed disturbing conditions for
inmates and guards in Louisiana's Winn Correctional Center, after
reporter Shane Bauer spent four months undercover as a prison
guard.

In the memo, Yates noted that private prisons "served an
important role during a difficult period," but ultimately fell
short on providing services, programs, and resources.

"Now with the decline in the federal prison population, we have
both the opportunity and the responsibility to do something about
that," Yates told
The Washington Post.

All private prisons housing federal inmates are run by one of
three companies: Corrections Corporation of America; the GEO
Group, Inc.; and Management and Training Corporation.